Who knew? Besides being headquarters of the International Longshoremen’s Association, the town of North Bergen, New Jersey, has a curious reputation as a hotspot for reported sightings of unidentified flying objects.

Surely just coincidence, of course. On the other hand, maybe the UFO connection is a clue to understanding the strange events last Friday, when an ILA wildcat strike shut the Port of New York and New Jersey in the middle of a busy day.

No other explanation seems to make sense.

This was an odd strike. There were no picket signs, and no warnings of an impending shutdown. Workers simply walked out at 10 a.m., leaving truckers, terminal officials and everyone else — including most dockworkers — wondering what was going on.

Days later, they’re still wondering.

Friday’s well-organized walkout apparently originated within the mechanics’ local headed by Dennis Daggett, the union’s executive vice president and son of ILA President Harold Daggett. Neither has commented on Friday’s events.

Official explanations have been murky. The ILA insisted the strike was an unsanctioned rank-and-file protest of actions by the Waterfront Commission of New York Harbor, and of issues involving chassis repair jurisdiction and technology.

Chassis and technology are real issues, but in this case they were secondary beefs. The protest’s main target was the Waterfront Commission, the anticrime watchdog that controls the port’s longshore register, licenses dockworkers and conducts investigations.

The ILA has bristled at commission efforts to change the waterfront culture by reducing the role of friends and family connections in hiring. In 2012 the union and its employers unsuccessfully sued the commission, claiming illegal interference in collective bargaining issues. A federal appeals court ruling is expected soon.

ILA officials also have been angered by commission’s investigations with other law-enforcement agencies into port-related crime. This appears to have been the most likely trigger for the walkout. Word on the waterfront is that lately, investigators have been taking an especially close look at certain ILA members’ timesheets.

If the reason for last week’s walkout remains vague, a deeper mystery is what ILA members hoped to achieve.

Strike organizers were foolhardy if they thought they could cause the Waterfront Commission to alter course. The port shutdown also is unlikely to strong-arm other parties to accept ILA positions on chassis or technology.

The ILA didn’t need to prove it could hobble the port in order to drive home a point. That’s been demonstrated repeatedly, for example with the four-day slowdown before Memorial Day in 2012 to protest a terminal’s firing of two no-show workers.

If the goal was to inflict maximum pain, last Friday was an ideal day. The East Coast’s busiest port was still catching up after a four-day closing for Winter Storm Jonas, following the Martin Luther King Jr. Day holiday the previous week.

ILA members will be spared the pain. They’ll be paid, mostly at overtime rates, to clear the container backlog. That’s not the case for trucking companies, drayage drivers, shippers, consignees and terminal operators hit with losses they can’t recoup.

As the port’s service providers and users try to get back on track, they’re hoping last Friday’s strike proves to be an event that’s isolated, albeit hard to explain — like some of those those UFO sightings in North Bergen.